Spark-plug.



W. C. FISCHER.

SPARK mus.

APPLICATION FILED FEB. 26,1917.

1 ,26'7,531. Patented May 28,1918.

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WILLIAM ones. i isonnn, or new rpnn, n. Y.

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Specification of. Letters Patent.

Patented May 28, 1918.

Application filed February 26, 1551.7. Serial No. 151,052.

To all whom it may cancer ii:

Be it known that I, WILLIAM (J. Freeman, a citizen of the United States, residing at New York, in the county of New York and State of New York, have inyented certain new and useful Iumrovements in Spark- Plugs; andl do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which .it appertains to make and use the same.

My invention has for its object to provide an improved type of spark plug having a multiplicity of spark gaps between the central electrode and that or those carried by the plug proper, thus. insuring that even though the jumping of the spark may be obstructed at certain points, it will be free to jum 9 at others.

ith the foregoing general object in View, the invention resides in certain novel features of construction and unique combinations of parts to be lu-rciuatter fully described and claimed, the descriptive matter being supplemented by the accompanying drawing which constitutes a part of this application and in which:

Figure l is a side elevation of one form of spark plug constructed in accordance with the invention;

Fig. 2 is a horizontal section on the plane of the line 2-2 of Fig. 1;

Fig. 3 is an enlarged sectional view through the lower end of the plug shown in Figs. 1 and 2;

Fig. l is a detail vertical section illustrating a different form of the invention;

Fig. 5 is a horizontal sectional view on the plane indicated by the line 5.5 of Fig. 4;

Fig. 6 is a View similar to Figs. 3 and 4: showing yet another form of construction; and

Fig. 7 is a horizontal SHEtlOTI on the plane of the line 7--7 of Fig. 6.

ln the drawing above briefly described, the numeral 1 has reference to the usual or any preferred type of hollow cylindrical plug externally threaded to be tapped into thev engine cylinder, said plug having a suitable lu-ad '2 for the application of a wrench. .'\n insulator 3 projects into the plug. through the upper end thereof and is secured. in place by any preferred means such as the nut or cap l, said insulator carrying the central electrode 5 whose upper end constitutes a binding post and is provided with a nut 6 for electrically connecting a wire to said electrode.

The lower end of the electrodefi projects into a preferably triangular opening 7 in a horizontal disk 8 which is spaced an appropriate distance below the plug 1, said disk being supported by electrodes 9 which are preferably three in number. The electrodes 9 may be constructed either as shown in Figs. 1 to 3 or in Figs. d and 5 but in either case, they will be provided with a plurality of pointed teeth 10 spaced a short distance from the electrode 5 to form a plurality of superimposed spark gaps.

The electrodes 9 of Figs. 1, 2 and 3 are stamped from sheet metal and at their upper ends are provided with vertical pins 11 suitably secured in vertical bores 12 which open through the lower end of the plug 1 at equally spaced points. The lower ends of the electrode 9 may be secured to the ring 8 in any preferred manner such as by electric welding but in the drawing I have shown said electrodes provided on their lower ends with integral studs 13 which are upset in circumi'erentially spaced openings formed through said ring.

In Figs. l and 5 the electrodes 9 and their teeth 10 are formed by bending short lengths of wire into zigzag formation. This construction can be manufactured more cheaply than that above described yet it Will be equally as ellieicnt. The u pper ends of the wire electrodes in'que'stion are shown anchorcd in bores similar to those indicated at 12 whereas their lower ends are shown as being upset in openingsin the ring 8. I will be understood, however, that other lower ends of the electrodes respectively to thc plug 1 and ring 8.

From the foregoing, taken in connection with the accompanying drawing, it will be observed that although the improved plug is of simple and inexpensive nature, it will be highly efficient and even though jumping of the spark between certain of the teeth 10 may be prevented, for instance, by deposits of carbon, the gaps between the other teeth and the electrode 5 will be snliicient to properly ignite the charge of gas in the cylinder. In addition to umping between points 10 and electrode 5 the "spark will are between said electrode and the three sides of the opening 7.

. means could well be employed for securing the upper and In the form of the invention shown in F 6 and T, the electrodes 9 are substantially the same those shown in Figs, Ti and The ring 8, however, is on'litted and the lower end of one of said electrodes is bent laterally at S beneath the central elec trode 5 to form an additional spark gap.

On account of the advantages derived, the types of electrode 9 illustrated, constitute the preferred forms thereof but it Will be understood that within the scope of the invention as claimed, numerous minor changes maybe made.

I claim:

A spark plug comprising a metal body, a ring disposed horizontally below said body and having a polysided central opening, a

- straight central electrode extending below said bod through said opening and insuee's 9531 lated from the former, the lower end of said electrode being spaced from the sides of said opening to provide a plurality of spark gaps, and a. plurality of vertical electrodes secured to said body and spaced around from said central. electrode to provide additional spark gaps. y

In testimony whereof I haYe hereunto set my hand in the presence of two subscribing Witnesses.

WILLIAM CHAS. FISCHER. lVitn'esses 2 Masons FRIEDLAKDER, WILLIAM DE KRUGER. 

